Food trucks? Apartments? Aluminum cabins? What to do with...

1of5Rubble lines the interior of the first BART car slated to be decommissioned as new trains enter the transit system’s fleet. The agency is seeking suggestions from the public on what to do with 669 older cars being replaced by the new Bombardier trains.Photo: Noah Berger / Special to The Chronicle

2of5Old BART cars become stackable homes in a sketch by Alfred Twu, who admits that backyard units would be more practical.Photo: Alfred Twu

3of5BART car 2528, slated to be the first decommissioned as new trains enter the transit system's fleet, rests at BART's Hayward, Calif., maintenance yard on Wednesday, Jan. 9, 2019. In the background is one of the new cars.Photo: Noah Berger, Special to The Chronicle

4of5An artist’s rendering depicts what the interior of a decommissioned BART car might look like if it were repurposed to create housing.Photo: Alfred Twu

5of5Rubble lines the interior of the first BART car slated to be decommissioned.Photo: Noah Berger / Special to The Chronicle

The possibilities for BART’s old, soon-to-be-junked legacy fleet seem endless. The cars could be revived as taco trucks, futuristic condos or rail-themed diners with Naugahyde seats.

They could be hollowed out and transformed into a lounge or gazebo, like one made from retired railcars at a Chicago apartment development. They could be shipped off to India or Bangladesh, decorated with bunting and repurposed on another municipal transit line. Or, if one BART enthusiast gets his way, the cars’ aluminum shells could be flattened and redesigned to make hot rods.

That last idea drew skepticism from BART spokesman Jim Allison, who had a different suggestion. “It might make more sense to make a Ken Kesey bus,” he said, referring to the psychedelic '60s road trip.

As the Bay Area transit agency introduces its new Bombardier fleet, officials are seeking suggestions from the public on what to do with 669 older cars, some of which have trundled along since the 1970s.

Fanciful renderings by artist Alfred Twu depict the possible reuse of decommissioned BART cars as housing. “The concept is not meant to be super-realistic,” the designer says.

Photo: Alfred Twu

BART’s board will hear a presentation Thursday on the challenge of decommissioning these vehicles by the target date of August 2023, roughly a year after officials expect to have all 775 new Bombardier cars.

“This schedule is a balancing act,” said special projects manager Philip Kamhi, who is handling the transition. He noted that BART has to keep enough trains in service to meet rising demand, while phasing out the old ones as new ones come in. That churn has to start this year, officials say, before the agency’s storage capacity runs out.

Aside from the urgency of their timeline, BART managers must also consider which train retirement options are most cost-effective. The Federal Transit Administration assisted in purchasing three of the four older fleets, and if those cars have a market value greater than $5,000 apiece, the administration is entitled to its share of the sales proceeds.

Then there are the limitations of BART’s aluminum frame, which in many ways is less durable than the carbon steel of the New York subway. That’s why BART officials couldn’t just dump the old cars into the ocean, the way their counterparts at New York’s Metropolitan Transportation Authority did when they turned antiquated subway trains into an artificial reef.

Special projects manager Philip Kamhi, who oversees the decommissioning of BART’s retired fleet, exits an old car at the Hayward maintenance yard.

Photo: Noah Berger / Special to The Chronicle

That idea may seem enticing, Kamhi said, but if BART cars were sunk in the briny bay, “they would degrade very quickly.”

But other ideas abound. The cars could be donated to trade schools for engineering classes, handed to the U.S. Army for drills, sold for scrap, placed in museums, reused as homeless shelters or tiny homes, converted to Airbnb vacation rentals or mothballed for special train service. The parts of some cars might be salvaged and transplanted like vital organs when a Bombardier car breaks down.

When BART announced its plan on Twitter this month, Berkeley artist and designer Alfred Twu replied with an architectural rendering of “aBARTments” — rail conveyances stacked like Jenga pieces atop a concrete building. With their metallic walls and sharp, geometric surfaces, the cars resemble an edgy high-rise.

As more new train cars arrive, the plan for what to do with the OLD cars is taking shape. The Board will hear a presentation next week about some options: Museums? Tiny homes? Pop-up food trucks? Scrap? Retiring them is not as easy as you might think. https://t.co/U2d58Xsw4qpic.twitter.com/UtDiRJyfLm

Rachel Swan covers transportation for The Chronicle. She joined the paper in 2015 and has also reported on politics in Oakland and San Francisco.

Previously, Rachel held staff positions at the SF Weekly and the East Bay Express, where she covered technology, law and the arts. She holds a Bachelor’s degree in rhetoric from the University of California, Berkeley.